【作者】 吴声敢；

【导师】 沈晋良；

【作者基本信息】 南京农业大学 ， 农药学， 2006， 硕士

【摘要】 本文以中国长江中下游地区稻田恶性杂草稗草为主要研究对象，系统研究了稗草的休眠特性及其解除方法，稗草对不同除草剂的敏感性，稗草对二氯喹啉酸的抗药性，并对二氯喹啉酸抗性稗草的防治进行了研究。结果如下：稗草在不同环境条件下的休眠特性研究结果表明，稗草种子在成熟后都将进入休眠，不同环境条件下其休眠期不一样。2004年7月采集的稗草种子在地下贮存条件下5个月就能打破休眠，但在次年7月份再次进入休眠。室内常温条件下需12个月才能打破休眠，而冰箱中贮存12个月不能解除稗草种子的休眠。采用机械损伤法有利于稗草种子休眠的解除。小穗顶端切口和末端切口处理均可解除稗草种子的休眠，其中小穗顶端切口的效果优于小穗末端切口。剥去颖壳处理只是部分解除稗草种子的休眠。通过1000mg／L赤霉酸一直浸泡、浓硫酸浸泡10-20min处理均能解除稗草种子的休眠，而其它处理不能有效解除稗草种子的休眠。在供试浓度下的萘乙酸、乙烯利和乙醇等均不能解除稗草种子的休眠。在稗草种子剥去颖壳的基础上，上述这些化学药（试）剂均可打破其休眠。采用滤纸法测定了稗草在不同处理时间下对15种除草剂的敏感性，确定了各除草剂的最敏感时间。其中吡嘧磺隆为2d，五氟磺草胺、丙炔噁草酮、二氯喹啉酸、双草醚、嘧啶肟草醚、嘧草醚和扑草净为3d，四唑酰草胺、噁嗪草酮、禾草敌和禾草丹则是4d，乙草胺、丁草胺和丙草胺以5d的结果为好。而滤纸法、琼脂法和盆栽喷雾法3种方法比较中，以琼脂法的敏感性为最高，能达到快速、灵敏的目的。应用琼脂法测定了15种除草剂在最敏感时间时的敏感性，并对其敏感性进行比较。结果表明，15种除草剂的敏感性大小顺序(根据EC₅₀值)为：噁嗪草酮、四唑酰草胺、乙草胺、丙炔噁草酮、丁草胺＞丙草胺、二氯喹啉酸、嘧草醚、五氟磺草胺、禾草丹、双草醚≥禾草敌、嘧啶肟草醚、吡嘧磺隆＞扑草净，为除稗剂的选择提供依据。选用琼脂法测定了43个稗草对二氯喹啉酸的抗性水平，结果表明采自浙江绍兴（2003年）的稗草对二氯喹啉酸最为敏感，其EC₅₀为0.3268mg／L。以采自浙江绍兴（2003年）的稗草为敏感稗草，采自浙江陶堰（2003年）和浙江塘下（2003年）的稗草对二氯喹啉酸的抗药性已达到了极高抗水平，抗性倍数分别为718.48倍和695.84倍。采自湖南安乡（2004年）和浙江杭州（2003年）的稗草对二氯喹啉酸也产生高水平抗药性，抗性倍数分别为62.21倍和41.22倍。而采自浙江皋埠（2003年）的稗草对二氯喹啉酸抗药性处于低水平抗性阶段，抗性倍数为6.41倍。其余38个稗草均对二氯喹啉酸敏感或处于敏感下降阶段。说明二氯喹啉酸抗性稗草已在湖南省和浙江省部分稻田产生。单剂量反应法和盆栽喷雾法也一致确定了采自浙江陶堰（2003年）、浙江杭州（2003年）和浙江塘下（2003年）的稗草已对二氯喹啉酸产生了抗药性。而且在浙江陶堰直播水稻田中进行的小区试验进一步确定了稗草对二氯喹啉酸的抗药性。应用琼脂法测定二氯喹啉酸抗性稗草和敏感稗草对不同除草剂的敏感性，结果显示二氯喹啉酸敏感稗草和二氯喹啉酸抗性稗草对乙草胺、丁草胺、丙草胺、五氟磺草胺、禾草丹、四唑酰草胺、噁嗪草酮和丙炔噁草酮等除草剂的EC₅₀值相近，表明二氯喹啉酸敏感稗草和二氯喹啉酸抗性稗草对这些除草剂的敏感程度是一致的，故这些除草剂可用于二氯喹啉酸抗性稗草的化学防除．田间小区试验法表明，丙草胺、双草醚和五氟磺草胺等除草剂可用于抗二氯喹啉酸稗草的田间防治。更多还原

【Abstract】 In this paper, the barnyard grass, a kind of worst weed in paddy field at the middle and lower Yangtze valley in China, was chosen as a main research object. The dormancy and its breaking methods of barnyard grass seeds, the susceptibility to different herbicides and the resistance to quinclorac of barnyard grass were studied systematically. Control of quinclorac-resistance barnyard grass was also studied in this paper. The results were as follows:The results of seed dormancy under different environmental conditions showed that the seeds of barnyard grass would get into dormancy after maturity, and the dormant period was different under different environmental conditions. The dormancy of barnyard grass seeds collected in July 2004 could be broken by buried in soil for 5 months, but they got into the second dormancy in the next July. The dormancy could also be broken by stored for one year under the room temperature. However, the seeds stored in refrigerator for one year were still dormancy.Mechanical damnification were advantageous in breaking dormancy of barnyard grass seeds. Cut at the top and cut at the end of the spikelets could broke dormancy of barnyard grass seeds, and the result of cut at the top excelled that cut at the end of the spikelets. Shelled spikelets only partly broken dormancy of barnyard grass seeds. The seeds were immersed in GA₃ with 1000 mg/L concentration or H₂SO₄ about 10-20 minutes could broke dormancy of barnyard grass seeds, but other disposal of GA₃ and H₂SO₄ could not broken dormancy of barnyard grass seeds. NAA, ethephon and ethanol could not broke dormancy under experimental concentration. However, on the base of shelled spilelets, GA₃, H₂SO₄, NAA, ethephon and ethanol could broken dormancy of barnyard grass seeds.The susceptibility of barnyard grass to 15 herbicides in different time were studied by filter paper method. The result showed the optimal time of barnyard grass to pyrazosulfuron-ethyl was 2 days. The best time of barnyard grass to penoxsulam, oxadiargyl, quinclorac, bispyribac-sodium, pyribenzoxim, pyriminobac-methyl and prometryn were 3 days. The most susceptibility time of barnyard grass to fentrazamide, oxaziclomefone, molinate and thiobencarb were 4 days. And the optimal time of barnyard grass to acetochlor, pretilachlor and butachlor were 5 days. Compared by agar method, filter paper method and pot-spraying method, the agar method was a most rapid and delicacy method in three kinds of methods to determine the susceptibility of barnyard grass to acetochlor, butachlor and quinclorac. Based on the EC₅₀, the susceptibility of 15 herbicides to barnyard grass by agar method is in the following order: oxaziclomefone, fentrazamide, acetochlor, oxadiargyl, butachlor＞pretilachlor, quinclorac, pyriminobac-methyl, penoxsulam, thiobencarb, bispyribac-sodium≥molinate, pyribenzoxim, pyrazosulfuron-ethyl＞prometryn.The resistant level of 43 barnyard grass collected from paddy fields in Zhejiang province, Jiangshu province, Anhui province, Jiangxi province and Hunan province were tested by agar method. The result showed the barnyard grass collected from Zhejiang Shaoxing in 2003 was the most susceptible barnyard grass to quinclorac, the EC₅₀ was 0.3268 mg/L. The barnyard grass collected from Zhejiang Taoyan（2003） and Zhejiang Tangxia（2003） were very high resistant to quinclorac, the resistance ratio were 718.48 and 695.84 respectively. The barnyard grass collected from Hunan Anxiang（2004） and Zhejiang Hangzhou（2003） were high resistant to quinclorac, the resistance ratio were 62.21 and 41.22. The resistant level of barnyard grass collected from Zhejiang Gaobu（2003） to quinclorac was low, the resistance ratio was 6.41. The other populations（38 populations） of barnyard grass were susceptible to quinclorac. So the resistant barnyard grass to quinclorac have been occurred in few paddy fields in Zhejiang province and Hunan province. The resistance of barnyard grass collected from Zhejiang Taoyan（2003）, Zhejiang Tangxia（2003） and Zhejiang Hangzhou （2003） to quinclorac were also be demonstrated by single dose assay and pot-spraying method. In field trials, the result showed the barnyard grass in direct-seeding paddy field of Zhejiang Taoyan were resistant to quinclorac.The susceptibility of resistant and susceptible barnyard grass to 8 herbicides were studied by agar method. The results exhibited the EC₅₀ of quinclorac-resistant barnyard grass to acetochlor, butachlor, pretilachlor, penoxsulam, thiobencarb, fentrazamide, oxaziclomefone and oxadiargyl were near that of quincloracsusceptible, and indicated the susceptibility of quinclorac-resistant and quinclorac-susceptible barnyard grass to these herbicides were same. So these herbicides can use for control of quinclorac-resistant barnyard grass. Pretilachlor, bispyribac-sodium and penoxsulam gave adequate control of quinclorac-rcsistant barnyard grass in field trials.更多还原